Hot tubs, spas, whirlpool bathtubs, whirlpool baths such as found in hospitals, nursing homes and rehabilitation facilities, and some swimming or wading pools, all of which generally being designated herein as immersion facilities, include water circulation lines and at least one pump that cooperate to circulate water between a water intake and jets positioned under the water level of the tub, spa or bath.
Generally, recreational or decorative fountains also circulate jetted water, which may be collected through drains into a holding tank, or which may fall into a decorative reservoir, between an intake in such holding tank or reservoir and jets or nozzles positioned so as to direct a stream or spray of water into the air. Recreational fountains include pop-up fountains or other fountains wherein children run through or otherwise play in water emitted therefrom. Since children, sometimes including toddlers still in diapers, or adults may play or wade in, and possibly ingest water from, either recreational or decorative fountains, it is desirable that water contained or recirculated therein be kept free of contaminants, particularly including pathogens such as cryptosporidia and the like which may cause harmful or even fatal infections of humans or other animals exposed to such water. There have been media reports that children have become severely ill from exposure to such pathogens which infect, survive, and multiply in recreational, pop-up, run-through fountains now found in many municipal and theme parks. Due to poor water quality in some areas, or because of contamination due to breaks or construction involving supply lines, it may also be desirable to treat water from a municipal water supply or other source with ozone even before initial use for bathing or other purposes in a water holding facility to kill pathogens and/or precipitate other contaminants. Such ozone treatments may be used in conjunction with other conventional sanitizing and sterilization techniques.
In many immersion facilities, air from an adjustable air valve or other ventilating system is mixed with the water circulated through jets or nozzles to increase impingement thereof on the body and skin of the user to promote muscle relaxation. In some hot tubs, spas, whirlpool baths, and similar facilities, injection of air into water contained within such immersion tubs or similar vessels, and into streams and jets of water flowing through plumbing, pumps, nozzles, and the like associated therewith, is enhanced by use of blowers, air pumps, or other air circulation or ventilating systems that are able to deliver significant quantities of air, e.g., up to 80 cfm, more or less, at pressures sufficient to overcome static or dynamic water pressure at a point of injection. For example, some tubs or other immersion vessels, in addition to mixing air into jets of water emitted typically from nozzles positioned around a periphery of a tub or other vessel, include a ventilating system and air jets or screened or porous openings incorporated into a bottom of a tub or other immersion vessel that emit air bubbles that impinge upon a user therein for therapeutic or relaxing benefit.
A problem with hot tubs and spas, other jetted bathing tubs, pools, fountains, or other water holding facilities, including recreational or decorative fountains, wherein water is kept over a period of time and reused is that if sanitizer levels are allowed to fluctuate then all manner of amoebas, bacteria, fungi, viruses, algae and other microbiota thrive on organic compounds present in the water. Harmful species of bacteria may also grow, such as listeria monocytogenes, which can cause pneumonia, meningitis and septisemia, and pseudomonas aeruginosa, which is responsible for pneumonia and skin rashes. While various strains of listeria may be eliminated by sanitizers and use of disinfectants, pseudomonas aeruginosa is a particularly resistant organism that defies most common sanitizers and antibiotics, and can grow at temperatures up to 42 degrees Celsius. Pseudomonas prefers moist and humid environments, and can survive even in distilled water. Worse yet, Legionella pneumophilia, the bacteria responsible for Legionnnaires disease, colonizes in amoebas that thrive in spas, hot tubs and jetted tubs, as well as showers, air conditioning evaporative cooling towers and other constantly wet or humid places. It is estimated that Legionnaires disease affects between 10,000-20,000 people per year, with a fatality rate of 5%-15% or more. Thousands more are probably infected, but are not severely sickened by the disease, developing only minor illness from the infections.
In addition to the foregoing, it is generally impossible to physically clean the interior of water and air-conveying tubes of the tub or spa as with the exposed surfaces thereof. As such, a “biofilm,” also called a “bioslime” herein and in some literature, of algae, fungus and a variety of bacterial colonies builds up on these interior surfaces of the tubes that is not removed by shocking the water and is not penetrated by sanitizer. As a result, a shocked immersion facility is immediately re-inoculated with bacteria, spores, or other pathogens from the bioslime upon refilling with fresh water.
As noted earlier herein with respect to decorative fountains, pop-up fountains, and other recreational fountains, water is generally captured directly in a reservoir or by gravity flow through drains and underground drain lines into a holding tank. Captured water is then recirculated by pumps or other means to jets through pressurizable distribution lines and other plumbing associated with a given fountain or fountain facility, which may include control valves to provide changes in water flow to selected nozzles to enhance decorative or recreational effects. Water is then typically released from these distribution lines in pulses or streams through fountain nozzles by valves, booster pumps, or other means. Some decorative or recreational fountain facilities are operated for a number or hours during daylight or early evening hours, then left dormant for a number of hours through the night, thereby enhancing opportunities for growth of biofilms, but also providing an opportunity, using apparatus and methods disclosed herein, to better treat biofilms and other contaminants. Wastes and other impurities that enter reservoirs or drains returning fountain water to a collection or holding tank further lead to contamination of water recirculated in such facilities and to conditions that promote growth of biofilms or other impurities within plumbing associated with such facilities. Thus, even where water in a collection reservoir is drained and replaced frequently with fresh water, biofilms and other contaminants in facility plumbing lines may quickly re-contaminate such fresh water.
Accordingly, there is a need, and as one object of the instant invention, to better sanitize hot tubs, spas, and all manner of jetted tubs, as well as decorative and recreational fountain facilities, to eliminate the above mentioned and other disease-causing organisms that live and grow in the water and air-carrying tubes of these tubs, spas, and other water holding facilities. The term water holding facilities, as used herein and in claims attached hereto, refers to and includes immersion facilities noted above as well as recreational or decorative fountains wherein contaminants may accumulate or multiply, including biofilms or bioslimes, which pose a threat to humans or other animals exposed to water therein or therefrom.
It is another object of the invention to provide apparatus and methods to enable convenient implementation, particularly in a retrofit installation, of treatment methods, including multi-phase treatment methods (described below), to oxidize and remove bioslimes and other organic contaminants in the water and air-conveying tubes of jetted tubs, spas, and fountains. It is yet another object of the invention to provide apparatus for retrofitting jetted tubs, spas, and fountains with an ozone generator communicating with water and air-carrying tubes of the system. In some embodiments, closed loop systems are disclosed that may be retrofitted or be installed during manufacture in order to prevent bubbles containing ozone from being returned to the immersion facility, these being particularly suitable for indoor use. Significantly, some of these systems are closed loop systems wherein bubbles that may contain ozone are prevented from being passed to the immersion facility. However, in other systems, bubbles containing ozone are intentionally released within plumbing and within water held within an immersion or reservoir portion of a facility in order to aid in treating chemical or biological contaminants in water held or circulated therein, and bioslimes or other deposits of contaminants that may develop within or upon pipes, pumps, and other assets associated with an immersion or fountain facility. In such embodiments, the use of injector or diffuser elements that produce small bubbles helps insure that most ozone is absorbed in the water, with little release of ozone into the air in an indoor immersion or other water holding facility.
In Applicant's prior patent application Ser. No. 09/197,036, which is hereby incorporated herein by reference in its entirety, filed Nov. 21, 1998, now U.S. Pat. No. 6,893,610, Applicant disclosed that an ability of ozone to break down long organic chains may be exploited to break down such contaminants adhering to walls of a ventilating system. Apparatus and a method for exploiting ozone in treating bioslimes within air and water passageways associated with jetted bathing facilities were disclosed in Applicant's application Ser. No. 09/520,504, hereby incorporated herein by reference in its entirety, filed Mar. 8, 2000, now U.S. Pat. No. 6,405,387. Apparatus disclosed herein are beneficial in helping extend application of this treatment method to break down and destroy long organic chains, including organics in biofilms, associated with ventilating system lines and other air passageways and plumbing and ventilating components associated with hot tubs, spas, and other water holding facilities. In Applicant's pending U.S. patent application Ser. No. 10/867,860, hereby incorporated herein by reference in its entirety, Applicant further disclosed how hydroxyl radicals and other ozonites produced by ozone generating ultraviolet lamps and ultraviolet destroying lamps, may be enhanced and controlled to a degree to increase effectiveness of treatment of contaminants, including biological contaminants.
It is another object of the invention to provide methods and apparatus for treating biofilms/bioslimes in a dry or moist state, when not covered with water (e.g., as in a drained water circulating line before an immersion facility is refilled with water for use), with a gas mixture including ozone in a gaseous state. It is another object of the invention to also provide convenient methods and apparatus for two-phase or multi-phase treatment of biofilms/bioslimes in both dry/moist states and in wet states, a wet state being when such biofilms/bioslimes are fully immersed in water, or nearly so. Such multi-phase treatments employ gaseous ozone in a gas mixture to treat biofilms/bioslimes in a dry/moist state, and employ ozone dissolved in water to treat biofilms/bioslimes when immersed in water. It is thought that different susceptibitilies and interaction mechanisms occur in the different states, which can be exploited in a multi-phase treatment methodology. For example, a multi-phase treatment methodology may comprise treating dry or moist biofilms with ozone in a gas mixture and subsequently treating the same biofilms when wet, i.e., covered with water, with ozone dissolved in such water, possibly also followed by another exposure to ozone gas of the biofilms just after water has been drained or otherwise emptied from a water circulation line, pipe, duct, or other passageway or surface (e.g., as a hot tub or whirlpool bathtub is being drained or just after draining) and is no longer covering the biofilm. In order to kill the cells in a bioslime, penetration into a biofilm/bioslime may be more important than just concentration of ozone. Single cell organisms may be lysed by a single ozone molecule. Ozone molecules in a gas have a much higher mean velocity than ozone molecules absorbed in water or another liquid and are thus able to penetrate deeper into the biofilm/bioslime than ozone molecules in a liquid. Additionally, when a biofilm/bioslime is dry, or only slightly moist, cracks or fissures may open in outer surfaces of the biofilm/bioslime due to drying and shrinkage of cells at or near the surface, thereby exposing cells normally protected by surface cells to direct attack by ozone molecules in a gas, and also creating more surface area that may be attacked directly by gaseous ozone. Furthermore, biofilms/bioslimes act as a semi-permeable membrane selectively passing ozone and ozone will then further break down the polysaccharide bonding material between cells in the biofilm/bioslime and further decompose structural strength of the biofilm/bioslime so that cells, or clumps of cells, formerly in the biofilm/bioslime, may be swept away by moving air or water. Alternately applying ozone in a gaseous state, then in a liquid absorbed state, further stresses the biofilm/bioslime, killing cells therein and weakening bonds so that components of the biofilm/bioslime may float away or be removed by motion of a fluid (i.e., gas or liquid) flowing by a thus weakened biofilm/bioslime. Applying ozone gas to a moist biofilm, just after water has been removed, further exploits the penetration capability of gaseous ozone when the biofilm is more active and expanded, and potentially more susceptible to damage by ozone. Applying ozone gas in higher concentrations, e.g., on the order of 100 ppm and higher, using techniques disclosed herein, has an advantage of destroying biofilms/bioslimes faster and apparatus and methods disclosed herein provide for controlling or reducing off-gassing or other release of ozone into air in a room containing a jetted tub or other bathing facility. Present day ozone producing vacuum ultraviolet lamps produce more ozone due to improved transmission of 185 nm wavelength radiation from the mercury vapor plasma in such lamps. However, features of the instant invention provide for control of air flow rates and time on to provide for intentionally limiting production or concentration of ozone. Other features control release of ozone into room air by blocking escape of ozone from air or water passageways, or by generating smaller bubbles of gas containing ozone, thereby improving absorption of ozone into water in a tub or flowing through a passageway. Accordingly, other systems, particularly retrofit systems, are also disclosed wherein one or more injectors used to emit ozone in a gas mixture into dry lines of a facility (i.e., before water is pumped into such lines), to treat biofilms, are subsequently used to continue to emit bubbles containing ozone into water in an immersion tub to enhance treatment of such water and other portions of a facility. Devices and treatment methods disclosed herein may also be used in numerous other applications where water standing in a line may promote growth of biofilms or bioslimes that may contaminate or recontaminate water flowing therethrough with harmful pathogens. Such other applications may include, for example, spray misters used in grocery stores to keep vegetables moist and fresh, or even lawn sprinkler systems. Such applications also include treating contaminants in water lines and ice containers in ice making or ice vending machines (e.g., such as associated with beverage dispensers in quick-stop service stations/grocery stores). Additional objects of the invention will become clear upon a reading of the following specification.